Focused ion beam (FIB) systems are known in the art. FIB systems are generally utilized to perform die milling and cross sectioning. The milled or cross-sectioned object is usually analyzed by an inspection device, such as a Scanning Electron Microscope (SEM), to detect defects. FIB systems can also be utilized to generate FIB images.
Various configurations of ion sources as well as voltage supplies and electrodes are known in the art. Some of these configurations are described at U.S. Pat. No. 6,472,881 of Sugiyama et al., U.S. Pat. No. 6,459,082 of Sakaguchi, U.S. Pat. No. 5,153,440 of Yasaka and U.S. Pat. No. 5,111,053 of Suzuki. All said patents are incorporated herein by reference. U.S. Pat. No. 6,472,881 describes an liquid metal ion source and a method for measuring flow impedance of liquid metal ion source. U.S. Pat. No. 5,111,053 describes a method for controlling a liquid metal ion source by analog feedback and digital CPU control. U.S. Pat. No. 5,153,440 describes a method for stabilizing operation for a liquid metal ion source. U.S. Pat. No. 6,459,081 describes a focused ion beam system.
A FIB system that is operative to generate a FIB image also has at least one detector and an image processor. Usually, the ion source, the FIB lens system and the ion beam deflector are located within a column that is commonly referred to as FIB column. The detector can also be placed within the FIB column.
SEM images are generated by irradiating an object with an electron beam, collecting signals resulting from an interaction of the electron beam with at least one portion of the object and processing the collected signals. FIB images are generated in a similar analogues manner, except that the object is irradiated with a focused ion beam.
Though separate SEM and FIB tools are quite common, systems that include both FIB and SEM systems are also available. These hybrid systems are known as FIB/SEM systems. The SEM portion of the hybrid tool facilitates inspection of a surface of an inspected object, such as a surface of a multi- layered die. The FIB portion of the hybrid systems facilitates milling the surface and exposing inner layers to inspection. Usually, after the FIB mills the die, the SEM is utilized to inspect the revealed layers and to further analyze the milled die for detecting defects. Two prior art FIB/SEM systems are the XL860 DualBeam Workstation of FEI or the SEMVisionG2 of Applied Materials Inc. of Santa Clara.
The XL860 includes a FIB column and SEM column that are angularly displaced from each other while the SEMVisionG2 includes substantially parallel SEM and FIB columns.
Typically, the focused ion beam is used to mill an object at certain intervals that are spaced apart from each other. Usually, once a wafer is milled or even partially milled it is inspected by the SEM, or by another tool.
Each liquid metal ion source has a predetermined amount of ions to provide. Thus, once the amount is provided the liquid metal ion source has to be placed or refilled. The replacement is time consuming and also costly. In some cases a liquid metal ion source replacement or re-filling procedure requires to open the FIB chamber, which is a time consuming procedure during which the vacuum level of the chamber (or even more than one level) must be restored. This opening may also expose the FIB. column to contaminations.
There is a need to provide an efficient system and method for improved utilization of liquid metal ion sources.